The present invention relates in general to wireline telecommunication systems and test equipment therefor, and is particularly directed to a physically compact, electronic xe2x80x98test tagxe2x80x99 device, that is readily connectable to a metallic wireline pair, such as at a minimum point of entry (at a customer premises) location, and contains circuitry that allows a remote test unit, such as may connected to a test switch matrix at a central office, to apply a prescribed electrical condition to the line. The test tag contains internal circuitry that responds to the applied electrical condition to controllably terminate the line in a selected one of an open loop or closed loop condition for test purposes. When terminating the line by a low valued resistance that closes a loop through the wireline pair, the test tag allows the connectivity of the subscriber line pair to be confirmed all the way from the central office to the test tag bridging location.
In the face of the increasing demand for a variety of high speed digital data communication services (such as, but not limited to HDSL, ADSL and SDSL), telecommunication service providers are continually seeking ways to optimize utilization of their very substantial existing metallic (e.g., copper) line pairs. Prior to the advent of digital communications, this copper plant was essentially employed for the purpose of carrying nothing more than conventional analog (plain old telephone service or POTS) signals.
When installing new lines, or when responding to a request by a competitive local exchange carrier (CLEC), such as an internet service provider (ISP), it may be necessary for the incumbent local exchange carrier (ILEC), such as a regional Bell operating company (RBOC), to dispatch a technician to a remote site serving customer premises equipment, for the purpose of verifying continuity of a wireline pair, through which (digital data) service supplied by the CLEC is provided to the customer""s data terminal equipment. Unfortunately, because of the wide variety of disparate methods currently employed by the CLEC""s and ILEC""s for activation and pre-service testing of subscriber line pairs, installation and delivery of service to subscribers is relatively cumbersome and slow.
In accordance with the present invention, this (digital subscriber) wireline connection verification problem is substantially mitigated by means of a physically compact, electronic xe2x80x98test tagxe2x80x99 device, which is configured to be readily connected to a location along the metallic wireline pair, such as but not limited to a minimum point of entry (MPOE) in the vicinity of customer premises equipment. The test tag contains circuitry that terminates the line in a prescribed resistance state in response to an electrical condition (such as a high or a low DC voltage) applied to the wireline by a remote test device, such as one connected to a test switch matrix at a central office.
In particular, the applied voltage will cause the test tag to selectively terminate the wireline by either a high resistance condition (e.g., on the order of 250 kohms or morexe2x80x94approximating an open circuit), or to bridge the wireline with a very low resistance (e.g., on the order of 200 ohms or less) that approximates an effective short circuit condition. For each terminated resistance condition the remote test unit may observe the characteristics of the line. Where the tag is placed in the effective short circuit bridging condition, it forms a loop with the two lines of the wireline pair, so that the test unit may confirm connectivity from the central office to the tag location.
The internal wireline termination circuitry of the test tag may comprise a pair of line-coupling terminals, that are bridged by a relatively high valued resistance, and by a voltage and current detector-controlled switch, that is coupled in circuit with a relative low valued resistor. This internal wireline termination circuitry is retained in a compact (e.g., palm-sized) housing or casing, and has its line-coupling terminals adapted to be connected to diverse types of lead terminations, such as free-ended wire xe2x80x98pigtailsxe2x80x99, an RJ-11 plug, a type 66 block clip, and the like, that extend externally of the test tag casing, so as to enable a craftsperson to physically connect the test tag to the wireline.
In an alternative configuration, the internal wireline termination circuitry of the test tag may comprise a commercially available maintenance test unit (MTU), that is retained in the test tag casing, and has a pair of network side or test source ports and a pair of subscriber drop ports. The network ports may be connected to diverse types of lead terminations, such as free-ended wire xe2x80x98pigtailsxe2x80x99, an RJ-11 plug, a type 66 block clip, and the like, extending externally of the test tag casing, so as enable a craftsperson to connect the test tag to the wireline. The subscriber drop ports are bridged internally of the test tag""s case by means of a relatively low resistance.
The test tag may be used when installing a new line or to troubleshoot existing cable plant. For a new installation, an ILEC cable plant installer connects a test tag to a network demarcation point of a newly installed unbundled wireline pair at a prescribed location (e.g., MPOE) near the subscriber premises. For troubleshooting an existing cable plant, the technician connects the tag to the wireline pair of interest, to allow remote verification testing. Once so connected, the test tag terminates the line with a circuit that allows a remote site to apply a selected high or low voltage to the line and thereby place the tag in a prescribed resistance state, as described above, so that connectivity of the wireline may be verified. Once the line has been verified, the installer removes the tag and connects the line to a subscriber drop for the CPE.